The Liberal Democrats will make a pre-Budget demand for a tax raid on the
pensions of middle-class professionals.

The party is to call formally for the Coalition to cut tax relief on pension contributions by higher-rate taxpayers, arguing that current rules give them an unfair benefit.

The party’s spring conference in Gateshead next month is also expected to reiterate the demand for a "mansion tax" on high-value properties.

The conference is likely to endorse a motion demanding that ministers take "immediate steps to ensure that wealthy individuals and businesses pay their fair share of tax". The motion calls for policies including "further limiting tax relief for payments into pension funds, which currently offers the greatest benefit to higher-rate taxpayers".

Workers who pay 40 per cent tax get 40 per cent relief on their pension contributions. Effectively, for every £1 invested in their pension fund, a worker only pays 60p.

The Treasury estimates that scrapping the 40 per cent relief would cost workers £7 billion a year.